Security Information and Event Management (SIEM) platforms play a critical role in modern cybersecurity by collecting, normalizing, and analyzing logs from multiple security devices. These logs help organizations detect threats, investigate incidents, and meet compliance requirements. A well-integrated SIEM environment relies on diverse security devices that generate high-quality logs. Below is a comprehensive and SEO-friendly overview of key security devices whose logs are commonly collected in SIEM, along with a few important additions that strengthen security visibility.
1. Next-Generation Firewalls (NGFW)
Next-Generation Firewalls are one of the most important log sources in SIEM. Unlike traditional firewalls, NGFWs provide deep packet inspection, application awareness, and threat intelligence integration. Logs from NGFWs typically include allowed and blocked traffic, application usage, intrusion attempts, and policy violations. These logs help security teams identify suspicious network behavior, malware communication, and unauthorized access attempts.
2. Web Application Firewalls (WAF)
Web Application Firewalls protect web applications from attacks such as SQL injection, cross-site scripting (XSS), and file inclusion. WAF logs provide detailed insight into HTTP requests, blocked payloads, attack signatures, and abnormal user behavior. When integrated with SIEM, these logs are invaluable for detecting web-based attacks and correlating them with other network or endpoint events.
3. DDoS Protection Devices
Distributed Denial of Service (DDoS) protection solutions generate logs related to traffic floods, volumetric attacks, and mitigation actions. SIEM correlation of DDoS logs helps identify attack patterns, source IPs, attack duration, and effectiveness of mitigation strategies. This visibility is essential for maintaining service availability and improving incident response readiness.
4. Load Balancers
Although often overlooked, load balancers are useful SIEM log sources. They manage traffic distribution across servers and generate logs on session requests, backend server health, and traffic anomalies. When analyzed in SIEM, load balancer logs help detect abnormal traffic spikes, service abuse, and early indicators of DDoS or application-layer attacks.
5. Proxy Servers
Proxy servers act as intermediaries between users and the internet, making them critical for monitoring user activity. Proxy logs capture URLs accessed, file downloads, blocked content, and user identities. SIEM analysis of proxy logs helps detect malicious websites, data exfiltration attempts, and policy violations, while also supporting user behavior analytics.
6. Antivirus and Endpoint Protection Platforms
Antivirus and endpoint security solutions generate logs related to malware detection, file quarantine, suspicious processes, and remediation actions. When these logs are forwarded to SIEM, security teams gain visibility into endpoint threats and can correlate them with network or email-based attacks, enabling faster containment and response.
7. Virtual Private Network (VPN)
VPN logs are essential for monitoring remote access and secure connectivity. These logs include login attempts, authentication failures, session duration, IP addresses, and geolocation data. SIEM correlation of VPN logs helps detect compromised credentials, unauthorized access, and abnormal login behavior such as impossible travel scenarios.
8. Data Loss Prevention and Detection Systems (DLP, IDS, IPS, EDR, IAM)
This category includes multiple advanced security technologies:
- DLP logs track sensitive data movement and policy violations.
- IDS/IPS logs record intrusion attempts and exploit signatures.
- EDR logs provide deep visibility into endpoint behavior and attack chains.
- IAM logs monitor authentication, authorization, and privilege changes.
Collecting these logs in SIEM enables advanced threat detection, insider threat monitoring, and compliance reporting.
9. Other Firewall Technologies
In addition to NGFWs, organizations often use cloud firewalls, internal segmentation firewalls, or legacy firewalls. Logs from these devices provide visibility into east-west traffic, internal threats, and hybrid infrastructure security. SIEM correlation helps identify lateral movement and misconfigured access rules.
10. Additional SIEM Log Sources to Consider
To enhance SIEM effectiveness, many organizations also collect logs from:
- Email Security Gateways – for phishing and spam detection
- Cloud Security Platforms (CASB/CSPM) – for SaaS and cloud workload monitoring
- Network Detection and Response (NDR) – for behavioral network analytics
- Operating Systems and Servers – for system-level security events
Including these sources improves threat coverage and reduces blind spots.
A SIEM solution is only as effective as the quality and diversity of logs it collects. Security devices such as firewalls, WAFs, DDoS protection systems, proxies, endpoints, and identity platforms form the backbone of SIEM visibility. By integrating logs from both traditional and advanced security devices, organizations can detect threats faster, respond more efficiently, and maintain a strong security posture. A well-designed SIEM log collection strategy is essential for proactive cybersecurity in today’s complex digital landscape.
